Proposed Wastewater Release into Cape Cod Bay Likely to Remain in Bay for at Least One Month, Study Finds
Woods Hole, Mass. (Dec. 4, 2024) -- Scientists at the Woods Hole Oceanographic Institution (WHOI) investigating the pathways of the proposed wastewater discharge from the Pilgrim Nuclear Power Station (PNPS) find it has a high probability of remaining in Cape Cod Bay for at least one month after release. Their findings are based on a model of the circulation patterns around Cape Cod Bay and provide insight into the seasonal differences in conditions in and around the Bay.
The study, “Model-based study of near-surface transport in and around Cape Cod Bay, its seasonal variability and response to wind,” was funded by WHOI Sea Grant and published in the Journal of Physical Oceanography.
“The spreading patterns of a plume depend on the timing of a release,” said Irina Rypina, the WHOI physical oceanographer who led the study. “We found virtually no out-of-the-Bay transport in winter and fall and slightly larger, but still low, probability of some of the plume exiting the Bay in spring and summer. These seasonal differences can be linked to different wind conditions that affect the circulation in and around the Bay throughout the year.”
Because activities taking place along the shores of Cape Cod Bay, such as tourism, commercial and recreational fishing, and aquaculture, are central to the region’s economy, the scientific paper focuses on investigating whether the plume water will spread toward the shoreline within the Bay or exit the Bay without approaching the inner-Bay shoreline. Based on the model, the first scenario is more likely. However, the results of the study cannot be used to draw conclusions about the environmental and human health and impacts of releasing the wastewater being stored at Pilgrim. Those impacts, as Rypina explained, depend on the specific chemistry of each isotope and the environmental conditions they may encounter.
The research team used a state-of-the-art, high-resolution ocean circulation model developed by the National Oceanic and Atmospheric Administration and applied it to look at the spreading of the wastewater plume in Cape Cod Bay. The model output was validated using observational data gathered earlier from drifters, free-floating buoys that are released in the ocean to measure currents. The research also focused on transport of wastewater released from Pilgrim in the upper 2 meters (6 feet) of the ocean, how it varies seasonally, and the role of wind as the driving force behind the spread of the wastewater plume.
“Our numerical simulations suggest it is unlikely that the bulk of plume waters will leave the Bay in less than a month,” Rypina said.
While more research would be needed to say how long it will take for the plume to leave the Bay, the researchers say it is likely to remain in the Bay for longer than a month, coming close to the shore, including coastal waters of Dennis, Wellfleet, and Provincetown. In addition, if the release were to happen in the spring and summer, a small portion of a plume might leave the Bay in less than a month, passing north of Provincetown and then flowing southward along the outer Cape.
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Links
- FAQ:Transport of Radioactive Contaminants in and around Cape Cod Bay
- Cafe Thorium - Dr. Ken Buesseler's lab at WHOI
- Model-based study of near-surface transport in and around Cape Cod Bay, its seasonal variability and response to wind (Journal of Physical Oceanography]